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A low-throughput method used to determine a portion of the nucleotide sequence of an individual’s genome. This technique uses polymerase chain reaction (PCR) amplification of genetic regions of interest followed by sequencing of PCR products.

Clinical evaluation of an asymptomatic individual in the general population aimed at identifying abnormalities which might signal the presence of a specific medical condition. The intent is to find diseases at the earliest possible stage in their development in order to improve the chances for cure or reduce morbidity.

The process of fitting formal genetic models to data on expressed disease characteristics (phenotype) in biological family members in order to determine the most likely mode of inheritance for the trait or disease under study.

The frequency with which a test yields a true positive result among individuals who actually have the disease or the gene mutation in question. A test with high sensitivity has a low false-negative rate and thus does a good job of correctly identifying affected individuals.

A single, isolated occurrence of an inherited condition in a family. Simplex cases can result from certain inheritance patterns or be caused by de novo mutations or reduced penetrance within the family. It can also result from nongenetic causes such as adoption or alternate paternity.

DNA sequence variations that occur when a single nucleotide (adenine, thymine, cytosine, or guanine) in the genome sequence is altered; usually present in at least 1% of the population. Also called SNP.

A laboratory test used to separate single-stranded nucleic acids based on subtle differences in their DNA sequence, often a single base pair, which results in a different secondary structure and a measurable difference in mobiity through a gel. Also called SSCP analysis.

DNA sequence variations that occur when a single nucleotide (adenine, thymine, cytosine, or guanine) in the genome sequence is altered; usually present in at least 1% of the population. Also called single nucleotide polymorphism.

An alteration in DNA that occurs after conception and is not present within the germline. Somatic variants can occur in any of the cells of the body except the germ cells (sperm and egg) and therefore are not passed on to children. Somatic variants can (but do not always) cause cancer or other diseases.

The frequency with which a test yields a true negative result among individuals who do not have the disease or the gene mutation in question. A test with high specificity has a low false-positive rate and thus does a good job of correctly classifying unaffected individuals.

A genetic alteration in the DNA sequence that occurs at the boundary of an exon and an intron (splice site). This change can disrupt RNA splicing resulting in the loss of exons or the inclusion of introns and an altered protein-coding sequence. Also called splice-site variant.

A genetic alteration in the DNA sequence that occurs at the boundary of an exon and an intron (splice site). This change can disrupt RNA splicing resulting in the loss of exons or the inclusion of introns and an altered protein-coding sequence. Also called splice-site mutation.

The process by which introns, the noncoding regions of genes, are excised out of the primary messenger RNA transcript, and the exons (i.e., coding regions) are joined together to generate mature messenger RNA. The latter serves as the template for synthesis of a specific protein.

This term has two meanings. It is sometimes used to differentiate cancers occurring in people who do not have a germline mutation that confers increased susceptibility to cancer from cancers occurring in people who are known to carry a mutation. Cancer developing in people who do not carry a high-risk mutation is referred to as sporadic cancer. The distinction is not absolute, because genetic background may influence the likelihood of cancer even in the absence of a specific predisposing mutation. Alternatively, sporadic is also sometimes used to describe cancer occurring in individuals without a family history of cancer.

A laboratory test used to separate single-stranded nucleic acids based on subtle differences in their DNA sequence, often a single base pair, which results in a different secondary structure and a measurable difference in mobiity through a gel. Also called single-stranded conformation polymorphism analysis.

The summation of all positive pedigree LOD scores (statistical estimates of whether two genetic loci are physically near enough to each other on a particular chromosome that they are likely to be inherited together) at each point in the genome. Also called summary logarithm of the odds score.

The summation of all positive pedigree LOD scores (statistical estimates of whether two genetic loci are physically near enough to each other on a particular chromosome that they are likely to be inherited together) at each point in the genome. Also called sumLOD score.

Periodic clinical evaluation of an individual who is at increased risk of developing a condition (compared with the general population) aimed at detecting new or recurrent disease. In public health, surveillance may also refer to the systematic collection of information regarding the incidence, prevalence, and mortality related to various medical conditions or health-related events.

A genetic alteration that increases an individual’s susceptibility or predisposition to a certain disease or disorder. When such a variant (or mutation) is inherited, development of symptoms is more likely, but not certain. Also called deleterious mutation, disease-causing mutation, pathogenic variant, and predisposing mutation.